postfix

# /etc/postfix/main.cf

# Identity
myhostname = vps1.richardmay.net
mydomain = richardmay.net
myorigin = $mydomain

# Network
inet_interfaces = loopback-only
inet_protocols = ipv4

# Don't accept mail for local delivery - send everything out
mydestination =
local_transport = error: local delivery disabled

# Relaying
mynetworks = 127.0.0.0/8 [::1]/128
relay_domains =

# TLS for outbound
smtp_tls_security_level = may
smtp_tls_loglevel = 1

# Default sender
sender_canonical_maps = static:vps1.do_not_reply@richardmay.net